The present invention relates to a suspension system for a vehicle, and more specifically to a decouplable stabilizer bar link arrangement which provides selectively increased suspension articulation.
Vehicles are commonly equipped with independent suspension systems for absorbing road shock and other vibrations while providing a smooth and comfortable ride for the vehicle occupants. In suspension systems of this type, a stabilizer bar is often used to increase the roll rigidity and improve the steering stability of the vehicle.
Typically, the stabilizer bar is an elongated member oriented to extend laterally across the vehicle with a first and second segment extending longitudinally at each end of the central segment. The central segment of the stabilizer bar is supported for rotation about its own longitudinal axis by one or more mounting brackets which are fixed to the vehicle body or frame. Each longitudinal segment is attached to a suspension member such as a control arm of the suspension system by an end link.
When the vehicle is subjected to a lateral rolling force such as, for example, while the vehicle negotiates a turn, the longitudinal segments pivot in opposite directions with respect to the longitudinal axis of the central segment. As a result, torsional reaction forces are generated which act through the segments to urge the suspension members to move toward their normal position. Thus, the vehicle body will be prevented from excessive rolling or leaning to either side by the torsional resistance produced by the stabilizer bar.
Increasingly desirable are vehicles such as Sport Utility Vehicles (SUVs) that combine the driveability characteristics of a passenger car with the ability to deliver off-road performance. One desired off-road performance characteristic of such a vehicle is the ability of the suspension to articulate through a larger range of motion. Increased suspension articulation improves control and traction when driving at slow speeds over large obstacles, such as rocks, ditches, logs, etc.
One of the drawbacks inherent in the use of stabilizer bars is that they trade suspension articulation for increased roll stiffness. As the vehicle suspension is forced through large displacements, the torsional resistance of the stabilizer bar prevents the suspension from attaining its maximum range of articulation.
In one known system an active link connects the stabilizer bar to the control arm. The active link assembly provides a controllable link which is actively adjusted to road conditions. However this known system requires a relatively complex rack and pinion gear arrangement. Further, movement of the link requires a large actuator assembly at each wheel which increases suspension system weight.
It is desirable to provide a stabilizer bar attachment arrangement that selectively permits the suspension to articulate free of stabilizer bar resistance during large suspension articulation. It would be particularly desirable to provide a lightweight selectively decouplable stabilizer bar link which does not require a complex actuator.
The suspension system according to the present invention provides a stabilizer bar which is attached to respective vehicle suspension members by decouplable end links. A first segment of each end link is attached to the suspension member while a second segment is attached to the stabilizer bar. The second segment preferably telescopes within the first segment to selectively decouple motion of the suspension members from the stabilizer bar.
The links are preferably in communication with a controller and sensors which sense motion of the suspension members. The controller interprets signals from the sensors and determines whether the links should be coupled or decoupled. Activation can be provided automatically through the controller or manually through a switch operated by the driver. The switch preferably includes an xe2x80x9con-roadxe2x80x9d and an xe2x80x9coff-roadxe2x80x9d setting.
In one embodiment a locking assembly includes an engagement member in the first segment which interacts with a groove in the second segment. When the engagement member is located in the groove, the end link is rigid and the stabilizer bar is linked to the suspension members to provide roll resistance in a known manner.
When the engagement member is released from the groove, the second segment is slidable relative to the first segment. Relative movement between the first segment and the second segment effectively decouples motion of the suspension member from the stabilizer bar. The affect of the stabilizer bar is thus removed and the articulation range of suspension system is increased as it is unhindered by the torsional resistance produced by the stabilizer bar.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows: